The interim Transport Ministry report released Friday said that a cell next to the one that began smoking partly melted, the Wall Street Journal reported. But the report said there was no drop in voltage in that cell.
The Federal Aviation Administration grounded all 787 Dreamliners in the United States in January 2013 after fires related to the battery unit, and some other countries followed suit. The separation of the battery cells was aimed at correcting the problem.
A lithium-ion battery unit in a Japan Air Lines Dreamliner began smoking while the plane was parked at Narita Airport in Tokyo, about to take off for Bangkok. Investigators said they found one of the cells swollen and with electrolyte evaporated.